﻿using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing.Text;
using System.Collections.Generic;
using System.Text;

namespace YAF.Classes.UI
{
    /// <summary>
    /// CaptchaImage Class
    /// Thanks to "prujohn" on the YAF Forum for his work.
    /// </summary>
    public class CaptchaImage : IDisposable
    {
        // Public properties (all read-only).
        public string Text
        {
            get
            {
                return this.text;
            }
        }

        public Bitmap Image
        {
            get
            {
                return this.image;
            }
        }

        public int Width
        {
            get
            {
                return this.width;
            }
        }

        public int Height
        {
            get
            {
                return this.height;
            }
        }

        // Internal properties.
        private string text;
        private int width;
        private int height;
        private string familyName;
        private Bitmap image;

        public CaptchaImage(string s, int width, int height)
        {
            this.text = s;
            this.SetDimensions(width, height);
            this.GenerateImage();
        }

        public CaptchaImage(string s, int width, int height, string familyName)
        {
            this.text = s;
            this.SetDimensions(width, height);
            this.SetFamilyName(familyName);
            this.GenerateImage();
        }

        private void SetDimensions(int width, int height)
        {
            if (width <= 0)
                throw new ArgumentOutOfRangeException("width", width, "Argument out of range, must be greater than zero.");
            if (height <= 0)
                throw new ArgumentOutOfRangeException("height", height, "Argument out of range, must be greater than zero.");
            this.width = width;
            this.height = height;
        }

        private void SetFamilyName(string familyName)
        {
            // If the named font is not installed, default to a system font.
            try
            {
                Font font = new Font(this.familyName, 12F);
                this.familyName = familyName;
                font.Dispose();
            }
            catch
            {
                this.familyName = System.Drawing.FontFamily.GenericSansSerif.Name;
            }
        }

        private void GenerateImage()
        {
            Random r = new Random();
            // Create a new 32-bit bitmap image.
            Bitmap bitmap = new Bitmap(this.width, this.height, PixelFormat.Format32bppArgb);

            // Create a graphics object for drawing.
            Graphics g = Graphics.FromImage(bitmap);
            g.SmoothingMode = SmoothingMode.AntiAlias;
            Rectangle rect = new Rectangle(0, 0, this.width, this.height);

            // Fill in the background
            HatchBrush hatchBrush = new HatchBrush(HatchStyle.SmallConfetti, Color.LightGray, Color.White);
            g.FillRectangle(hatchBrush, rect);

            // Set up the text font
            SizeF size;
            float fontSize = rect.Height + 1;
            Font font;
            // Adjust the font size until the text fits within the image.
            do
            {
                fontSize--;
                font = new Font(this.familyName, fontSize, FontStyle.Bold);
                size = g.MeasureString(this.text, font);
            } while (size.Width > rect.Width);

            // Set up the text format.
            StringFormat format = new StringFormat();
            format.Alignment = StringAlignment.Center;
            format.LineAlignment = StringAlignment.Center;

            // Create a path using the text and warp it randomly.
            GraphicsPath path = new GraphicsPath();
            path.AddString(this.text, font.FontFamily, (int)font.Style, font.Size, rect, format);
            float v = 4F;
            PointF[] points = 
            {
                new PointF(r.Next(rect.Width) / v, r.Next(rect.Height) / v),
                new PointF(rect.Width - r.Next(rect.Width) / v, r.Next(rect.Height) / v),
                new PointF(r.Next(rect.Width) / v, rect.Height - r.Next(rect.Height) / v),
                new PointF(rect.Width - r.Next(rect.Width) / v, rect.Height - r.Next(rect.Height) / v)
            };
            Matrix matrix = new Matrix();
            matrix.Translate(0F, 0F);
            path.Warp(points, rect, matrix, WarpMode.Perspective, 0F);

            // Draw the text
            hatchBrush = new HatchBrush(HatchStyle.LargeConfetti, Color.LightSkyBlue, Color.DarkGray);
            g.FillPath(hatchBrush, path);

            // Add some random noise
            int m = Math.Max(rect.Width, rect.Height);
            for (int i = 0; i < (int)(rect.Width * rect.Height / 30F); i++)
            {
                int x = r.Next(rect.Width);
                int y = r.Next(rect.Height);
                int w = r.Next(m / 50);
                int h = r.Next(m / 50);

                g.FillEllipse(hatchBrush, x, y, w, h);
            }

            // Clean up
            font.Dispose();
            hatchBrush.Dispose();
            g.Dispose();

            // Set the image
            this.image = bitmap;
        }

        #region IDisposable Members
        void IDisposable.Dispose()
        {
            GC.SuppressFinalize(this);
            this.image.Dispose();
        }
        #endregion
    }
}
